// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <cstdint>

// Upper bound accepted by IndexingSettings::RefineThreads. Callers deriving a thread count from the
// machine must clamp to it - on a big host -N/2 exceeds it and the setter throws.
constexpr int MAX_REFINE_THREADS = 64;

enum class IndexingAlgorithmEnum {FFBIDX, FFT, FFTW, Auto, None};
// Flex = "let the pipeline decide": try several per-image refinements and keep whichever indexes the
// most spots (CLI -r flex; the legacy -r multi name is still accepted as an alias).
enum class GeomRefinementAlgorithmEnum {None, OrientationOnly, BeamCenter, Flex};

class IndexingSettings {
    IndexingAlgorithmEnum algorithm;
    int64_t fft_num_vectors = 16*1024;
    float fft_max_unit_cell_A = 500.0;
    float fft_min_unit_cell_A = 10.0;
    float fft_max_angle_deg = 150.0;
    float fft_min_angle_deg = 30.0;
    float fft_high_resolution_A = 2.0;
    float indexing_tolerance = 0.1;
    float max_angle_from_ewald_deg = 2.0;
    float unit_cell_dist_tolerance_vs_reference = 0.05; // relative
    static constexpr float unit_cell_angle_tolerance_deg = 5.0; // degree
public:
    // The longest cell the FFT search can be asked to reach, and so the longest it can ever find:
    // FFTIndexer sizes its histogram from fft_max_unit_cell_A and the transform's last usable bin IS
    // that length. Callers that widen the bound (a given cell, the long-axis rescue) must clamp to
    // this rather than let the setter throw - a rescue that recovers an implausible axis must not
    // take the whole run down with it.
    static constexpr float fft_max_unit_cell_limit_A = 1200.0;
    // The other end of the same search: any candidate whose reduced cell has an axis shorter than
    // fft_min_unit_cell_A is discarded, and this is the lowest floor the setter accepts. A caller
    // lowering the floor to reach a given cell clamps to it rather than let the setter throw.
    static constexpr float fft_min_unit_cell_limit_A = 5.0;
private:
    int64_t indexing_threads = 4;
    // Threads splitting the candidate-cell refinement WITHIN one indexer call. 1 (the default) is the
    // right answer whenever indexers already run one per image across all workers; it is raised only
    // where few indexer threads exist and cores would otherwise sit idle.
    int64_t refine_threads = 1;
    // The setter's own floor. A frame that carries fewer spots than this cannot validate a
    // lattice, and on a weakly diffracting crystal a bar set above what its frames can reach
    // is arithmetic rather than evidence: the true lattice is found, indexes every frame it
    // can, and is refused because too few frames could clear a count they never had the spots
    // for. The fraction of frames that must validate is the gate that carries the meaning.
    //
    // It is NOT only the validation bar, and lowering it loosens more than that: the same number
    // is the order statistic the candidate scorer ranks cells on, the stopping condition of the
    // iterative residual contraction, and the adoption gate of per-frame refinement (see
    // PostIndexingRefinement.cpp). Those three want a count that makes a fit trustworthy, which
    // is not the same question as whether a frame had spots to spare, and they are coupled here
    // only because one constant has always served both.
    int64_t viable_cell_min_spots = 6;

    int64_t max_extra_lattices = 2;

    bool blocking_behavior = true;
    bool index_ice_rings = false;

    // Refuse the Bravais class the metric was promoted to on a LENGTH equality, and index in the
    // class left when that equality is struck out. Not a user setting: rugnux runs one pass with it
    // and one without, and keeps the one whose re-integrated held-out positional residual is lower
    // (see RunAllPasses). The promotion is decided against a 3 % relative tolerance on a cell the
    // spot positions place to ~0.1 %, so on a small cell a genuinely orthorhombic crystal is
    // integrated with a = b imposed and nothing downstream can recover from it.
    bool lattice_class_demoted = false;

    bool enable_rotation_indexing = false;
    float rotation_indexing_min_angular_range_deg = 20.0;
    float rotation_indexing_angular_stride_deg = 0.5;

    GeomRefinementAlgorithmEnum refinement = GeomRefinementAlgorithmEnum::BeamCenter;
public:
    IndexingSettings();

    IndexingSettings& ViableCellMinSpots(int64_t input);
    IndexingSettings& Algorithm(IndexingAlgorithmEnum input);
    IndexingSettings& FFT_MaxUnitCell_A(float input);
    IndexingSettings& FFT_MinUnitCell_A(float input);
    IndexingSettings& FFT_MaxAngle_deg(float input);
    IndexingSettings& FFT_MinAngle_deg(float input);
    IndexingSettings& FFT_NumVectors(int64_t input);
    IndexingSettings& FFT_HighResolution_A(float input);
    IndexingSettings& Tolerance(float input);
    IndexingSettings& IndexingThreads(int64_t input);
    IndexingSettings& RefineThreads(int64_t input);
    IndexingSettings& UnitCellDistTolerance(float input);
    IndexingSettings& GeomRefinementAlgorithm(GeomRefinementAlgorithmEnum input);
    IndexingSettings& IndexIceRings(bool input);
    IndexingSettings& RotationIndexing(bool input);
    IndexingSettings& RotationIndexingMinAngularRange_deg(float input);
    IndexingSettings& RotationIndexingAngularStride_deg(float input);
    IndexingSettings& BlockingBehavior(bool input);
    IndexingSettings& MaxExtraLattices(int64_t input);
    IndexingSettings& LatticeClassDemoted(bool input);

    [[nodiscard]] int64_t GetViableCellMinSpots() const;
    [[nodiscard]] IndexingAlgorithmEnum GetAlgorithm() const;
    [[nodiscard]] GeomRefinementAlgorithmEnum GetGeomRefinementAlgorithm() const;
    [[nodiscard]] float GetFFT_MaxUnitCell_A() const;
    [[nodiscard]] float GetFFT_MinUnitCell_A() const;
    [[nodiscard]] int64_t GetFFT_NumVectors() const;
    [[nodiscard]] float GetFFT_HighResolution_A() const;
    [[nodiscard]] float GetTolerance() const;
    [[nodiscard]] float GetFFT_MinAngle_deg() const;
    [[nodiscard]] float GetFFT_MaxAngle_deg() const;
    [[nodiscard]] int64_t GetIndexingThreads() const;
    [[nodiscard]] int64_t GetRefineThreads() const;
    [[nodiscard]] float GetUnitCellDistTolerance() const;
    [[nodiscard]] float GetUnitCellAngleTolerance_deg() const;
    [[nodiscard]] bool GetIndexIceRings() const;
    [[nodiscard]] bool GetRotationIndexing() const;
    [[nodiscard]] float GetRotationIndexingMinAngularRange_deg() const;
    [[nodiscard]] float GetRotationIndexingAngularStride_deg() const;
    [[nodiscard]] bool GetBlockingBehavior() const;
    [[nodiscard]] int64_t GetMaxExtraLattices() const;
    [[nodiscard]] bool GetLatticeClassDemoted() const;
};